7.0 Issues

Peter Haworth pete at lcsql.com
Thu Feb 19 23:15:06 CET 2015


Ho Eric,
Spoke too soon.  Your code wont compile in versions prior to 7 because of
the extra parameter.  I guess I could compile it in 7 but that would mean I
would have to compile that script in 7 every time I wanted to make a change
and there's a lot of handlers in it so high probability of changes.  I
suppose I could use a do statement (yuk).

The more I think about this, the more it's a pretty bad backward
compatibility problem.  I'm wondering if the dictionary entry is in fact
the way it was supposed to be implemented, meaning if the new parm isn't
present the old encoding is used.

You only care about the new encoding if you're storing unicode data in an
array and doesn't seem like any more of an imposition to use the new
parameter than having to use textEncode/Decode for other unicode operations.

On Thu Feb 19 2015 at 1:03:05 PM Eric Corbett <eric at canelasoftware.com>
wrote:

> I think what you will have to do is this:
>
> Check the LC version;
> if it’s >= 7 then
> arrayEncode(tData,6) — force the engine to use the old arrayEncoding
> else
> arrayEncode(tData) — older versions can not have the extra parameter
> end if
>
> LiveCode 7 will be smart enough to decode the array either way.
>
> Eric
>
> On Feb 19, 2015, at 12:49 PM, Peter Haworth <pete at lcsql.com> wrote:
>
> > Thanks Eric, yes that does indeed help.  However, I'm still confused.
> The
> > dictionary indicates that if the new parameter, version, is not present
> > then arrays are encoded the old way.  None of my calls include the new
> > parameter so not sure how they ended up being inaccessible in pre7
> versions.
> >
> > I guess the gist of my post was what else have I failed to account for?
> Is
> > there a document somewhere that details what code structures may need
> > attention when moving back and forth between LC7 and prior versions?  I'm
> > guessing that anything addressing char chunks or offset would need to be
> > changed.
> >
> > On Thu Feb 19 2015 at 12:31:24 PM Eric Corbett <eric at canelasoftware.com>
> > wrote:
> >
> >> Not sure if this helps, but LiveCode 7 uses a different arrayEncoding
> than
> >> previous version due to Unicode. Check the dictionary on how to use
> >> arrayEncode in 7 to be able to decode in an earlier version.
> >>
> >> Eric
> >>
> >>
> >>
> >>
> >> On Feb 19, 2015, at 12:16 PM, Peter Haworth <pete at lcsql.com> wrote:
> >>
> >>> I've been careful to create separate versions of my stack files and
> >>> Livecode Preferences folder for use when running LC 7.  However, it
> seems
> >>> there other issues with compatibility.
> >>>
> >>> I save the preferences for my application in a file in the
> >>> /Library/Application Support folder with the following statement:
> >>>
> >>> *write* base64Encode(arrayEncode(gSettings)) to file <filepath>"
> >>>
> >>> These are then read in at startup with:
> >>>
> >>> read from file myPath until EOF
> >>>  if it is empty then
> >>>     put empty into gSettings
> >>>  else
> >>>     put arrayDecode(base64Decode(it)) into gSettings
> >>>  end if
> >>>
> >>> Yesterday, I started working on this stack with LC7 and the prefs file
> >> was
> >>> saved by the LC7 version of the stack.
> >>> Today, I needed to go back to the non LC7 version of the stack.  To my
> >>> surprise, a runtime error was thrown on the "put arrayDecode..."
> >> statement
> >>> above.  The  it variable looked  like it contained base64 encoded data.
> >>>
> >>> I ran the LC7 version of the stack again and the runtime error did not
> >>> occur.
> >>>
> >>> I restored the preferences file from a Time Machine backup that I know
> >>> preceded my use of LC7, ran the application again with LC 6.6.2, and
> all
> >>> worked fine.
> >>>
> >>> So it seems that something in either the array/base64 encode/decode
> >>> functions changed between v6.6.2 and 7.0.1.
> >>>
> >>> I really want to use LC7 but stuff like this makes me very nervous.
> How
> >>> many other inconsistencies like this are lurking out there.
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